Espinel’s final day on the job was Friday. Howard Shelanski, administrator of the Office of Information and Regulatory Affairs, will serve as acting head until President Obama names a successor.

In a position that was dubbed “IP czar” or “copyright czar,” Espinel was responsible for coordinating anti-piracy and anti-counterfeiting initiatives across federal agencies. A 2008 federal law signed by President George W. Bush and backed by the entertainment industry called for such a position in the White House.

During her tenure, Espinel encouraged private sector initiatives to combat piracy, including a set of “best practices” unveiled by ad networks last month. Other “best practices” have been put in place by advertisers and payment processors, and the entertainment industry came to an agreement with major Internet providers to implement as system of copyright alerts. That system was launched earlier this year.

While she advocated for some stronger laws, like increasing the punishment for illegal streaming of copyrighted content, it was a different story when it came to the Stop Online Piracy Act.

The legislation, aimed at curbing rogue sites that operated overseas, was criticized by many Silicon Valley firms, and in a statement at the time Espinel took issue with some of the bill’s provisions. The White House’s opposition to parts of the legislation only seemed to escalate an online protest against SOPA, and the bill was sidelined the following week.

Espinel’s tenure also saw increased enforcement activity by customs officials and the FBI.

Michael O’Leary, senior executive VP for global policy at the MPAA, said in a statement that Espinel “has been an inportant force in advocating for the meaningful protection of American creativity here and around the world. We have appreciated her commitment to a collaborative process as well as her leadership on these issues that are so crucial to the continued strength of our economy.”

In a statement, he said that Espinel “brought to a demanding job thoughtfulness, credibility and diligence. She was tirelessly inclusive and worked hard to listen to everyone who wanted to be part of the conversation. As a result, the administration spoke with a more unified and informed voice on intellectual property issues, and spearheaded important initiatives.”